The Atchafalaya River Basin: Conservation and Restoration in America’s Largest Swamp.

Bryan P. Piazza Director, Freshwater and Marine Science

The Nature Conservancy Baton Rouge, Louisiana

© Brittany App

The Mississippi River Drainage Basin

• Original basin over 3,000 mi2. • Now 1- million acres.

• 5th largest river by discharge.

• Distributary system for the Lower

Mississippi River.

The Atchafalaya River Basin

© The Nature Conservancy

Protection Levees Old River Control Structure

Channel Training and Distributary Closure

© Alison Jones

Flood Control

© The Nature Conservancy

Navigation

© Alison Jones

Timber Resources

© The Nature Conservancy

Oil and Gas

© The Nature Conservancy

Forests

Actively Building Delta

© The Nature Conservancy

Biodiversity Hotspot

© The Nature Conservancy

© The Nature Conservancy © Charles Bush

Biodiversity Hotspot

© The Nature Conservancy

© TNC © Joel Sartore

Nutrient and Carbon Sequestration

© Brittany App © TNC

Heartbeat of the Cajun Culture

© The Nature Conservancy

© Erik Canning

River-floodplain Interaction

System-wide Flow Regulation

© The Nature Conservancy

Canals and Levees

Flow Barriers

Forests Degrade and Cannot Regenerate

© Brittany App

Hypoxia

Tools and Approaches

• Science • Conservation • Partnerships

• Hydrologic Restoration • Land Protection • Stakeholder Relations • Decision Making

• Working at all levels of our organization and with many partners.

1. The Atchafalaya River Basin: History and Ecology of

an American Wetland

• Scientific baseline.

• Adds to existing science tools.

• Informs work of TNC and partners.

• State will use in restoration planning.

Piazza, BP. The Atchafalaya River Basin: History and Ecology of an American Wetland. Texas A&M University Press, In Press.

1. Spatial analysis to determine highest-priority conservation areas in the ARB. 2. Assessed landowner support. 3. Determined market-based conservation price-points.

2. Land Protection

Piazza, BP, YC Allen, R Martin, JF Bergan, K King, R Jacob. Floodplain Conservation in the Mississippi River Valley – Combining Spatial Analysis, Landowner Outreach, and Market Assessment to Enhance Land Protection for the Atchafalaya River Basin, Louisiana, USA, Restoration Ecology, Submitted.

Why?

• Assist the USACE in meeting land protection targets.

• Develop platform preserve (~ 5,000 acres). • Enhance land protection by attracting

other public and private funds (e.g., WRP, HB 219).

• Use ARB as a system-wide floodplain model.

Priority Conservation Areas 6 PCAs - 190,000 acres. • 21 – 38% suitable for regeneration • 2 – 21% suitable for regeneration

and high water quality index

Landowner Support • Contacted landowners held 63% of

PCAs. • 80% of contacted landowners were

interested in land protection programs.

Land Protection Values $500 – $1,000 USD acre-1

• USACE value - $140 acre-1

• Additional restrictions – up to $900 acre-1.

Developed a GIS suitability analysis to determine areas most suitable for hydrologic restoration and baldcypress regeneration. Objectives:

– Inform land protection efforts. – Fit into existing restoration

efforts. – Improve landowner outreach

through visualization. – Provide a flexible framework

that can be modified and expanded.

3. Hydrologic Restoration and Landowner Outreach

Hayden, A, BP Piazza, DP Harlan, JF Bergan. Combining GIS suitability analyses, hydraulic modeling, and stakeholder input to enhance environmental decision making in the Atchafalaya River Basin, Louisiana. In Prep.

Baldcypress Regeneration Hydrologic Restoration

Suitability Surfaces

Project-level Restoration Scenario Analysis

Hydraulic modeling at water management unit (WMU) scale.

Testing planned project features to quantify how these will improve flow/water quality. What is the impact of recommended project features? Optimize desired project effects with cost-benefit and landowner willingness to participate.

Developed a process for applying Structured Decision Making to restoration planning in the Atchafalaya Basin.

Restoration Decision Making

Kozak, JP and BP Piazza. A proposed process for applying structured decision making to restoration planning in the Atchafalaya River Basin, Louisiana, USA. Restoration Ecology, Submitted.

Acknowledgements

• LDNR Atchafalaya Basin Program

• Yvonne Allen, US Fish and Wildlife Service

• Southern Illinois University

• National Science Foundation

• National Audubon Society